I use a kobo- has a blue light filter, waterproof, backlight. Not sure about the selfhosted library, I throw everything into memory which is enough for thousands of books.

Anything but amazon.

Linux only.

No, I meant what is the user limit based on the power of the raspberry pi tech specs.

What user cap would a pi have running an instance?

I imagine they’re working on it right now - likely this weekend perhaps?